I am a newbie to this forum. I own and ride a low-mileage 1980 KZ1300 with the original CCT. I have purchased the ZX11 tensioner and gasket (Part #'s 12048-1113 and 11009-1858, respectively). To avoid the potential incremental wear on the nylon sprocket from the increased pressure of the ZX11 tensioner (even with 10-12mm removed from spring length), I was wondering whether this ratchet-type mechanism could be run in manual mode by not installing the spring? In other words, could I install the ZX11 tensioner with the ratchet fully retracted, then press the ratchet mechanism against the chain and rely upon the ratchet to stay in place without the spring? If the ratchet could be depended upon to hold without the spring, I would just periodically check the tensioner as one would do with a manual model. I would welcome feedback on this idea.
I don’t have a ZX11 cam chain tensioner, and I’m not sure if what you are proposing would be a safe modification. I think that without the spring in place, there would’ve some ‘chattering’ of the mechanism, which is undesirable. Have you searched this forum for cam chain tensioner information? There is enough to keep you reading for at least one hour! So many differing opinions on the best solution to the flawed original design. I share your concern about the ZX11 spring strength being too great. To my mind, it is not as simple as cutting 10mm off the spring length to achieve an acceptable pressure on the tensioner assembly. Yet, many knowledgeable 1300 owners put their trust in that solution. I have not yet commenced the restoration of my A4 model, but when the time comes, my inclination is to retain the original tensioner, though with one small change - to the 6mm bolt / set screw in the side of the tensioner - I shall replace that with a longer one ( with turned down diameter at the end) so that the tensioner shaft can be locked in position when it has taken up the slack in the chain. The bolt needs to be long enough so that a lock but an be tightened against the tensioner body.
I have used the original tensioner with one modification. I have changed the 6 mm. original limiter bolt to one which is ca. 10 mm longer and have a locknut in it. I set the tensioner when engine is hot and then use the longer bolt to lock the shaft, tighten the locknut. Then check once every 3000 miles/5000 km. Has worked fine for me the past 30.000 km.
I pasted the late Lare Nurminen’s post, which explains better what I was trying to say.
Hopefully, other members will give their opinions on this subject.
Please tell us about what motivated you to become a KZ1300 owner. Also, some photos of your bike would’ve nice to see, along with your experience of ownership. Thank you.
Everyone assumes that the excessive wear on the nylon tensioner sprocket is due to excess pressure of the tensioner spring. I'll play the Devil's advocate and suggest that quite possibly the excessive wear is due to a loose sloppy chain bouncing off of the nylon sprocket. The stock KZ1300 tensioner is known for not locking properly in a tensioned state and that could account for a loose chain bouncing around. Something needs to be done to ensure that the stock tensioner doesn't back right off and allow the chain to become so loose that the camshafts can jump a tooth and bend valves.
Somewhere along the times, someone compared the spring wire diameter between the KZ1300 tensioner and the ZX11 spring and the zx11 spring wire diameter was thicker so yes the rate of increase of the spring would be more. No one has actually measured the spring pressure of the KZ1300 spring at a mid stroke length and compared it to the spring pressure of a cut zx11 spring at the same length so if you do chose to go ahead with the mod and install a modified zx11 tensioner, you might want to compare the springs from both the KZ1300 tensioner and the zx11 tensioner and "try" to achieve the same spring force as the stock tensioner..
Installing the zx11 tensioner without the spring could work if you were to manually push on the back of the tensioner's rod and then replace the bolt and copper gasket but how much pressure will you put on the end of the rod?? You might put too much and then the ratchet would lock it in that position. Sounds like a crap shoot to me.